Progress and Challenges in Coupled Hydrodynamic-Ecological Estuarine Modeling

Numerical modeling has emerged over the last several decades as a widely accepted tool for investigations in environmental sciences. In estuarine research, hydrodynamic and ecological models have moved along parallel tracks with regard to complexity, refinement, computational power, and incorporation of uncertainty. Coupled hydrodynamic-ecological models have been used to assess ecosystem processes and interactions, simulate future scenarios, and evaluate remedial actions in response to eutrophication, habitat loss, and freshwater diversion. The need to couple hydrodynamic and ecological models to address research and management questions is clear because dynamic feedbacks between biotic and physical processes are critical interactions within ecosystems. In this review, we present historical and modern perspectives on estuarine hydrodynamic and ecological modeling, consider model limitations, and address aspects of model linkage, skill assessment, and complexity. We discuss the balance between spatial and temporal resolution and present examples using different spatiotemporal scales. Finally, we recommend future lines of inquiry, approaches to balance complexity and uncertainty, and model transparency and utility. It is idealistic to think we can pursue a theory of everything for estuarine models, but recent advances suggest that models for both scientific investigations and management applications will continue to improve in terms of realism, precision, and accuracy

Firm performance in networks: the interplay between firm centrality and corporate group size

Corporate groups or networks, which are defined as collections of two or more legally independent firms connected through ownership ties, are prevalent in both developed and developing countries. The separate effects of firm centrality and corporate group size on firm performance have been largely discussed in the literature. However, the effect of their interaction remains underexplored. This paper attempts to fill the gap by introducing a new normalized measure of firm centrality independent of corporate group size. Our empirical analysis is based on a set of global corporate networks encompassing 17.8 million firms and the ownership ties between them extracted from the ORBIS database in 2014. We further investigate the firm performance in the corporate networks above by gathering financial information on 483,835 Italian firms from the AIDA database from 2014 to 2016. We find a positive relationship between firm centrality and firm performance, but the significance of the relationship decreases as corporate group size increases

Taste evaluation of potato glycoalkaloids by the Aymara: A case study in human chemical ecology

A chemical ecological model can be the basis for defining testable hypotheses concerning human interactions with plants. Selection by Aymara subsistence cultivators against toxic glycoalkaloids in the ongoing domestication of the Bolivian potato cultigen Solanum X ajanhuiri was used as a specific case study of human interactions with phytochemicals. In taste perception tests, Aymara subjects were able to discriminate between concentrations of pure glycoalkaloids in solution only above 20 mg/100 ml. Taste panel tests of potato clones indicated that glycoalkaloid levels are important to the Aymara in determining quality only as part of a decision-making process involving two character states: too high or acceptable. Glycoalkaloids in potatoes are regarded as toxic to humans above 20 mg/100 g fresh weight. Among the Aymara, a breakpoint in the curve for glycoalkaloid preference appears to occur between 20–38 mg/100 g. This distinction is evident in the Aymara potato taxonomy which distinguishes bitter (luq'i ch'oke) from nonbitter (ch'oke) potatoes .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44480/1/10745_2004_Article_BF00888308.pd

R&D investment, firm performance and moderating role of system and safeguard: Evidence from emerging markets

The relationship between R&D and firm performance is highly dependent on the external environment. Therefore, this paper examined the effects of country level investor protection (safeguards) and governance mechanisms (systems) on the relationship between R&D and firm performance. Using GMM estimation and elasticity testing of panel data for 423 firms from 12 emerging countries, we find that a country's safeguards tend to moderate the relationship between R&D and firm performance more than the system of a country. The results indicate that safeguarding is relatively more important for the relationship between R&D and firm performance than other country level governance mechanisms, as the former can easily attract outside capital when it is strong. These results have significant implications for innovation policy. In particular, managers may wish to strengthen investor protection to promote high R&D investment in order to increase firm performance

Leveraging the macro-level environment to balance work and life: an analysis of female entrepreneurs' job satisfaction

This study investigates the interactive effect of female entrepreneurs’ experience of work–life imbalance and gender-egalitarian macro-level conditions on their job satisfaction, with the prediction that the negative linear relationship between work–life imbalance and job satisfaction may be buffered by the presence of women-friendly action resources, emancipative values, and civic entitlements. Data pertaining to 7,392 female entrepreneurs from 44 countries offer empirical support for these predictions. Female entrepreneurs who are preoccupied with their ability to fulfill both work and life responsibilities are more likely to maintain a certain level of job satisfaction, even if they experience significant work–life imbalances, to the extent that they operate in supportive macro-level environments

Lampsilis teres, Specimen #416

One preserved mussel specimen including the left valve only. The specimen exhibits an elliptical shape; moderately thick shell; white internal coloring; tan external coloring; no external sculpturing. Collected in the Brazos basin. The specimen measures between 100 - 120 mm in length and was assessed to be long dead when collected

Potamilus purpuratus, Specimen #689

One preserved mussel specimen including the right valve only. The specimen exhibits a rhomboidal shape; thick shell; white internal coloring; brown external coloring; no external sculpturing. Collected in the Brazos basin. The specimen measures between 60 - 100 mm in length and was assessed to be live when collected